Real time text (RTT) allows for a near instantaneous transmission of text content between Internet Protocol (IP)-based terminals. As a user of a source device types a RTT message, the text content of the RTT message is displayed on a destination device in real-time, without requiring the user of the source device to select a “send” button. This near instantaneous transmission of text content resembles a more natural conversation that is preferred by the hearing and speech impaired over traditional text messaging (e.g., Short Message Service (SMS) text). RTT also allows both parties of a communication session to type concurrently (e.g., allowing one user to interrupt the other user), and RTT can be implemented as an add-on to voice, which enables simultaneous voice and RTT media streams. A voice call that allows for the transmission of text content via an RTT media stream (in parallel with voice) is sometimes referred to as a “RTT call”.
The Federal Communications Commission (FCC) has mandated that certain wireless carriers support RTT technology earlier than others, which means that some carrier networks may not support RTT technology for some time, even though many mobile handsets will be capable of making RTT calls on carrier networks that support the technology. Furthermore, it is possible that a RTT-capable handset will fail to establish a RTT call, even when a RTT-capable carrier network is available to the handset. This may be due to RTT-related network outages impacting the entire RTT call (not just the text component of the call). When a user cannot establish a RTT call, the user may be forced to redial in an attempt connect the call. This needlessly consumes network bandwidth, and it can be inconvenient for a user making a non-emergency call. In emergency situations, a failure to connect the user can delay emergency responders, which may cause harm to people in emergency situations. Furthermore, if a handset is preconfigured to establish a call as a RTT call by default, a user may have to open a settings menu to change the behavior of the handset so that calls will be made as voice-only (i.e., non-RTT) calls. This time consuming process to change call settings on the handset can also be dangerous in emergency situations because a delay in responding to an emergency situation can have serious consequences.